Infineon Technologies T740N24TOFXPSA1

Overview

T740N24TOFXPSA1 from Infineon Technologies is a high-power phase-control thyristor designed for industrial AC power regulation in medium- to high-voltage line-commutated converters. It delivers 745 A average on-state current at 85 °C case temperature, supports 2400 V repetitive peak off-state voltage (V_DRM/V_RRM), and withstands 13 kA non-repetitive surge current (t_P = 10 ms) - enabling use in 3-phase rectifiers, motor soft-starters, and static VAR compensators.

For engineers reviewing the T740N24TOFXPSA1 datasheet, T740N24TOFXPSA1 pinout, T740N24TOFXPSA1 application, or T740N24TOFXPSA1 equivalent, key selection criteria include gate trigger current (≤250 mA), critical dv/dt rating (1000 V/µs), junction-to-case thermal resistance (0.028 °C/W two-sided), on-state voltage (1.32 V at 650 A), and commutated turn-off time (300 µs).

Technical Context

This thyristor operates as a line-commutated, gate-controlled semiconductor switch in phase-angle controlled AC systems. Its design centers on robust latching (1500 mA) and holding (300 mA) currents, low slope resistance (0.5 mΩ), and precise gate triggering (V_GT ≤ 2.2 V, I_GT ≤ 250 mA) under full junction temperature range (−40 °C to +125 °C).

Thermal performance is defined by dual-sided cooling capability, with transient thermal impedance Z_thJC modeled analytically across seven RC network elements. The device requires external forced commutation or natural current zero-crossing for turn-off, and its 300 µs circuit commutated turn-off time (t_q) is validated at V_RM = 100 V and dv_D/dt = 20 V/µs.

Key Specifications

Pinout & Package

Package: TO-240AA (also designated "TO-240" or "TO-240AA"), a pressure-contact, stud-mounted, double-sided cooled thyristor housing with isolated anode/cathode terminals and flat gate contact. Requires clamping force of 10.5–21 kN for reliable thermal and electrical interface.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar phase-control thyristor applications.

Compared with TT740N24KOF and T740N24KO, the T740N24TOFXPSA1 offers superior thermal performance (0.028 °C/W), integrated auxiliary cathode for enhanced gate drive integrity, and optimized flat gate geometry - making it preferred for new high-density, high-reliability industrial power converter designs.

Availability

T740N24TOFXPSA1 is available at Aetrix Electronics and suitable for industrial motor soft-starters, medium-voltage rectifier bridges, and static VAR compensators requiring stable component supply, long-term lifecycle support, and traceable sourcing from original manufacturer stock.

Supply support for T740N24TOFXPSA1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Infineon Technologies is a German semiconductor manufacturer specializing in power electronics, automotive ICs, and industrial control solutions, with global manufacturing and quality certification to ISO/TS 16949 and IECQ QC 080000.

This thyristor belongs to Infineon's "Netz-Thyristor" product line, engineered specifically for high-reliability, high-power AC line-commutated applications including grid infrastructure, heavy industrial drives, and metallurgical process control.

FAQ

What is the maximum allowable case temperature for continuous operation?

The T740N24TOFXPSA1 supports continuous operation with case temperature (T_C) up to +125 °C when mounted with two-sided cooling and operated within its I_TAVM = 745 A rating at that temperature. Derating is required above this point; the datasheet provides TC vs. ITAV curves for 30°–180° conduction angles under both sinusoidal and rectangular current waveforms.

Does this thyristor require a snubber circuit?

Yes - due to its 1000 V/µs critical dv/dt rating, a properly designed RC snubber is required across the anode–cathode terminals in most inductive-load applications to prevent false turn-on during voltage transients. Snubber values must be calculated based on load inductance, switching frequency, and expected dv/dt stress, per Infineon Application Note AN2001.

Can the auxiliary cathode terminal be left unconnected?

No - the auxiliary cathode (terminal 5) must be connected to the main cathode (terminal 2) via a low-inductance path, typically using a dedicated strap or busbar. Leaving it floating degrades gate trigger sensitivity, increases required I_GT, and raises risk of erratic turn-on under high di/dt conditions.

What gate drive voltage and current are needed for reliable turn-on?

A minimum gate trigger voltage of 2.2 V and current of 250 mA must be delivered within 4 µs (t_gd) at 25 °C. At maximum junction temperature (125 °C), gate drive energy must meet P_GM = 20 W for 10 ms pulses (curve 'a' in datasheet Fig. 8), requiring ≥3.5 V and ≥500 mA peak for robust margin in industrial environments.